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Siloxane Molecular Glue for Ultrarobust Interface Engineering in High-Performance Colloidal Quantum Dot Infrared
Haipeng Su1, Jingjing Wang1, Chengjie Deng1
1Wuhan National Laboratory For Optoelectronics (WNLO) and School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, P. R. China.
Advanced Materials (Deerfield Beach, Fla.)
|July 28, 2026
Summary
We developed a new interfacial layer for colloidal quantum dot photodiodes, enhancing mechanical stability and reducing defects. This improves infrared imaging performance and dark current in quantum dot devices.
Area of Science:
- Materials Science
- Optoelectronics
- Nanotechnology
Background:
- Colloidal quantum dot (CQD) photodiodes suffer from interfacial defects and poor mechanical robustness, limiting infrared imaging applications.
- Existing interfacial layers often fail to provide sufficient mechanical adhesion or prevent defect formation.
Purpose of the Study:
- To introduce a bifunctional organosilane, (3-mercaptopropyl) methyldimethoxysilane (MDMS), as an interfacial layer to improve CQD photodiode performance.
- To address challenges in mechanical robustness and interfacial defects in inverted PbS CQD photodiodes.
Main Methods:
- Utilized MDMS to form covalent bonds at the CQD/electron transport layer (ETL) interface via thiol coordination and siloxane network formation.
- Engineered the interface to improve mechanical adhesion and provide a nucleation surface for atomic layer deposition (ALD) of SnO2 ETL.
- Fabricated and characterized inverted PbS CQD photodiodes with the MDMS interfacial layer.
Main Results:
- Achieved significantly improved mechanical adhesion (5B rating) compared to controls (0B/1B).
- Suppressed interfacial defects and island-like growth of ALD-grown SnO2 ETL.
- Optimized devices exhibited a specific detectivity of 2.37×10^12 Jones at 1550 nm and 79% EQE at -0.1 V, with >50% reduction in dark current.
- Monolithic integration with a silicon ROIC resulted in a SWIR imager with low photoresponse non-uniformity (2.8%) and high spatial resolution (26 lp/mm).
Conclusions:
- MDMS effectively enhances mechanical robustness and passivates interfacial defects in CQD photodiodes.
- The developed interfacial strategy enables high-performance infrared imaging with CQD photodiode technology.
- Demonstrated the potential for CQD photodiode integration with silicon readout integrated circuits (ROICs) for advanced imaging systems.
